Seasonal variation of Ralstonia solanacearum biovar 2 populations in a Spanish river: recovery of stressed cells at low temperatures

The presence of Ralstonia solanacearum biovar 2 in the watercourses of European countries is increasing, but little is known about its ecology in aquatic habitats. The detection of this pathogen in 2000 in one Spanish river led us to study its population density at different locations on the river over a period of 3 years. During 2000 and 2001, the pathogen was recovered at low densities (10 to 80 CFU/ml) by direct plating on modified SMSA agar from water samples at 14 degrees C or higher, but its isolation was usually unsuccessful at temperatures below 9 degrees C. To monitor the pathogen's abundance in winter, we used two liquid selective media for enrichment (at 29 and 35 degrees C) and compared them by using spiked river water samples: modified Wilbrink broth (MWB) was more efficient than modified SMSA broth for double-antibody-sandwich indirect enzyme-linked immunosorbent assay (DASI-ELISA) detection of R. solanacearum. Enrichment in MWB at both temperatures allowed us to recover R. solanacearum cells that were nonculturable on solid media up to 25 days after their entry into the viable but nonculturable state. When we applied this technique to water samples during the cold months of 2001 and 2002, we obtained the best detection results by the most-probable-number method after enrichment at 35 degrees C with MWB. The enrichment protocol was combined with DASI-ELISA and validated by Co-PCR to detect both naturally and artificially starved and cold-stressed cells in water, which were still infective. Overall, the data from this study demonstrate the effects of temperature variation on the population and culturability of R. solanacearum cells on solid media and their survival at low temperatures.     

Attenuation of lipid peroxidation and hyperlipidemia by quercetin glucoside in the aorta of high cholesterol-fed rabbit

Antioxidative activity of dietary flavonoids is suggested to be, at least partly, responsible for a wide variety of their biological effects relating to anti-atherosclerosis. However, it is not known whether dietary flavonoids reach to the target site and act as antioxidants. In this study, we tried to evaluate the antioxidative effect of quercetin 3-O-beta-D-glucoside (Q3G), a typical flavonoid present in vegetables, in rabbit aorta. New Zealand White rabbits were fed a control diet (control group), 2.0% cholesterol diet (HC group) and 2.0% cholesterol plus 0.1% Q3G (HC + Q3G group) for one month. The amounts of total cholesterol, triacylglycerol and total fatty acids in both the plasma and aorta were significantly lower in the HC + Q3G group as compared with the HC group. Quercetin was detected in the aorta of the HC + Q3G group after enzymatic deconjugation, indicating that quercetin accumulated as conjugated metabolites in the aorta. The contents of TBA-reacting substances (TBARS) and cholesteryl ester hydroperoxides (CEOOH) in the aorta of the HC + Q3G group were significantly lower than those in the HC group. The aorta of HC + Q3G group was more resistant than that of HC group in copper ion-induced lipid peroxidation ex vivo. HC + Q3G group accumulated a higher amount of vitamin E per total cholesterol than HC group in the aorta. These results strongly suggest that quercetin glucosides accumulate in the aorta as their metabolites and attenuate lipid peroxidation occurring in the aorta, along with the attenuation of hyperlipidemia.     

Exploring the genome of Trypanosoma vivax through GSS and in silico comparative analysis

A survey of the Trypanosoma vivax genome was carried out by the genome sequence survey (GSS) approach resulting in 1,086 genomic sequences. A total of 455 high-quality GSS sequences were generated, consisting of 331 non-redundant sequences distributed in 264 singlets and 67 clusters in a total of 135.5 Kb of the T. vivax genome. The estimation of the overall G+C content, and the prediction of the presence of ORFs and putative genes were carried out using the Glimmer and Jemboss packages. Analysis of the obtained sequences was carried out by BLAST programs against 12 different databases and also using the Conserved Domain Database, InterProScan, and tRNAscan-SE. Along with the existing 23 T. vivax entries in the GenBank, the 32 putative genes predicted and the 331 non-redundant GSS sequences reported herein represent new potential markers for the development of PCRbased assays for specific diagnosis and typing of Trypanosoma vivax.     

Mastication effort study using photorefractive holographic interferometry technique

The purpose of this work was the force–displacement response analysis of the masticatory process in a dried human skull by Double-Exposure Photorefractive Holographic Interferometry Technique (2E-PRHI). The load concentration and dissipation of the forces from dried human skull were analysed at applied loading stands as a Simulation of Isolated Contraction (SIC) of some mastication muscles. The 2EHI and Fringe Analysis Method were used to obtain the quantitative results of this force–displacement response. These results document quantitatively the real biomechanical response from dried human skull under applied loading and it can be used for complementary study by finite element model and others analysis type.     

Polymorphic and differential expression of the Trypanosoma cruzi alleles containing universal minicircle binding protein

DNA replication mechanisms are poorly understood in most of trypanosomatids, in particular the replication of the peculiar mitochondrial DNA, the kinetoplast DNA (kDNA). To contribute to the knowledge on the mechanism of kDNA replication in Trypanosoma cruzi, we have previously characterized the Universal Minicircle Sequence Binding Protein of this parasite (TcUMSBP), which was first called PDZ5 [E.R. Coelho, T.P. Urmenyi, J. Franco da Silveira, E. Rondinelli, R. Silva, Identification of PDZ5, a candidate universal minicircle sequence binding protein of Trypanosoma cruzi, Int. J. Parasitol. 33 (2003) 853-858]. In this work, we describe two highly polymorphic alleles of the TcUMSBP locus in the T. cruzi reference clone CL Brener and the differential expression pattern of these alleles. A 62 bp sequence in the TcUMSBP upstream intergenic region in one of its alleles affects the efficiency of polycistronic RNA processing and the polyadenylation sites, and therefore regulates the differential expression of TcUMSBP alleles of this locus.     

The functional effect of soybean extract and isolated isoflavone on myocardial infarction and ventricular dysfunction: The soybean extract on myocardial infarction

BackgroundMyocardial infarction is a public health problem. Functional food is an alternative treatment for cardiovascular diseases.ObjectiveThe objective was to analyze the functional and anatomopathological post-myocardial-infarction effects of soybean extract (SE) and isoflavone (IF).MethodsMyocardial infarction was induced in adult Wistar rats. After 5 days, an echocardiogram was performed to determine heart rate (HR), ejection fraction (EF), systolic volume (LVESV) and diastolic volume (LVEDV). Animals with ventricular dysfunction (EF<45%) were selected for study. The animals were divided into three groups: control (n=14), SE (n=15) and IF (n=12). The IF group received 120 mg/kg/day isolated IF, and the SE group received 12.52 g/day. After 30 days, a new echocardiogram was performed. A histological exam was carried out to determine the collagen. Activity of biochemical markers [arginase, lactate dehydrogenase (LDH) and malate dehydrogenase] was measured.ResultsThe animals of the control, IF and SE groups showed a reduction in EF after the infarction (P=.432, P=.017 and P=.320, respectively). An increase of LVESV and LVEDV was observed in all groups (P=.009, P=.001 and P=.140; and P=.003, P=.008 and P=.205, respectively). A reduction of HR was found in the SE group (P=.020). There was a greater activity of LDH in the SE group. A smaller quantity of mature collagen was found in the region proximal to the myocardial infarction in the SE group.ConclusionA protective effect in the SE group was observed 30 days after the myocardial infarction.     

Predicting arsenic bioavailability to hyperaccumulator Pteris vittata in arsenic-contaminated soils

Using chemical extraction to evaluate plant arsenic availability in contaminated soils is important to estimate the time frame for site cleanup during phytoremediation. It is also of great value to assess As mobility in soil and its risk in environmental contamination. In this study, four conventional chemical extraction methods (water, ammonium sulfate, ammonium phosphate, and Mehlich III) and a new root-exudate based method were used to evaluate As extractability and to correlate it with As accumulation in P. vittata growing in five As-contaminated soils under greenhouse condition. The relationship between different soil properties, and As extractability and plant As accumulation was also investigated. Arsenic extractability was 4.6%, 7.0%, 18%, 21%, and 46% for water, ammonium sulfate, organic acids, ammonium phosphate, and Mehlich III, respectively. Root exudate (organic acids) solution was suitable for assessing As bioavailability (81%) in the soils while Mehlich III (31%) overestimated the amount of As taken up by plants. Soil organic matter, P and Mg concentrations were positively correlated to plant As accumulation whereas Ca concentration was negatively correlated. Further investigation is needed on the effect of Ca and Mg on As uptake by P. vittata. Moreover, additional As contaminated soils with different properties should be tested.     

Sweet block copolymer nanoparticles: preparation and self-assembly of fully oligosaccharide-based amphiphile

The preparation of biocompatible nanocarriers that have potential applications in the cosmetic and health industries is highly desired. The self-assembly of amphiphilic block copolymers displaying biosourced polysaccharides at the surface is one of the most promising approaches. In the continuity of our works related to the preparation of "hybrid" amphiphilic oligosaccharide-based block copolymers, we present here the design of a new generation of self-assembled nanoparticles composed entirely of oligosaccharide-based amphiphilic block co-oligomers (BCO). These systems are defined by a covalent linkage of the two saccharidic blocks through their reducing end units, resulting in a sweet "head-to-head" connection. As an example, we have prepared and studied a BCO in which the hydrophilic part is composed of a free maltoheptaosyl derivative clicked to a hydrophobic part composed of a peracetylated maltoheptaosyl derivative. This amphiphilic BCO self-assembles to form spherical micelles in water with an average diameter of 30 nm. The efficient enzymatic hydrolysis of the maltoheptaose that constitutes the shell of the micelles was followed by light scattering and colorimetric methods.